Water treatment system

ABSTRACT

A water treatment system for removing hard ions from source water. The water treatment system is of the type that includes a pair of ion-exchange water softener tanks connectable to a source of pressurized water and with a water system to supply softened water to the water system, the tanks each being capable of regeneration by flushing with a regeneration solution to replenish depleted ions. A process for preventing system failure due to salt crystallization includes flowing water during brine replenishment from a second nozzle and a first nozzle at a defined ratio. The first nozzle diluted the brine in a reservoir after regeneration cycle is complete. The second nozzle replenishes brine by flowing water directly onto a salt material.

FIELD OF INVENTION

The present invention relates to a water treatment system. Morespecifically, the present invention relates to an improved brine valveand use thereof in a water treatment system.

BACKGROUND OF THE INVENTION

Household water softeners of the “ion exchange” type typically include aresin tank through which hard water passes to exchange its “hard” ionsof calcium and magnesium for “soft” sodium or potassium ions from theresin bed. Regeneration of the resin bed is periodically required toremove the accumulation of hard ions and replenish the supply of softions. Regeneration is effected by flushing a solution of salt, i.e., abrine solution through the resin bed.

A separate brine tank is conventionally used to form the brine solutionfor use during the regeneration cycle. When regeneration is initiated inthe softener system, the brine solution drawn from the brine tank passesthrough the bed of ion exchange material in the softener tank to reversethe exchange of ions and revitalize the bed by removing hardnessinducing ions and replacing them with sodium or potassium ions from thebrine. The regeneration cycle typically lasts about an hour and needs tobe done, on average, about three or four times each week. More frequentregenerations are required in periods of greater than normal waterusage. No regeneration is required when water usage ceases as typicallyhappens when the occupants of a household go on a holiday or vacation.The cost of operating a water softener system may be reduced by limitingthe amount of salt utilized in each regeneration cycle and the frequencyof regeneration cycles to only that necessary to regenerate resinparticles. Consequently, it is preferred that the brine solution have aconcentration near its saturation point to minimize the amounts used foreach regeneration cycle. Saturated solutions are less desirable sincethe salt in these solutions have a tendency to crystallize.

Most present day water softeners use a single resin tank for softeningand are provided with automatic controls to regenerate the softeningtank at periodic intervals. A drum containing a brine solution istypically connected to the resin tank and includes a concentratedaqueous solution of sodium chloride or potassium chloride. As previouslydiscussed, the concentration of sodium chloride or potassium chloride isbelow the saturation point for the solution. However, the solubilitycharacteristics for sodium chloride and potassium chloride aresignificantly different.

One problem addressed by the present invention is the difference insolubility behavior between various salts used as softeners, e.g.,potassium chloride and sodium chloride. Sodium chloride solubility isless sensitive to temperature fluctuations than potassium chloridesolubility. For example, at 0° C. the solubility of sodium chloride inwater is about 35.7 grams per cubic centimeter (g/cc) of saturatedsolution whereas potassium chloride is about 27.6 g/cc. Increasing thetemperature to 10° C. increases the solubility of a saturated sodiumchloride solution to 35.8 g/cc and a saturated potassium chloridesolution to 31.0 g/cc. Further incremental increases to 20° C. and 30°C. increase solubility of a saturated sodium chloride solution to 36.0g/cc and 36.3 g/cc, respectively, whereas the solubility of a saturatedpotassium chloride solution increases to 34.0 g/cc and 37.0 g/cc,respectively. Clearly, the solubility of sodium chloride solutions areless sensitive to temperature fluctuations. Conversely, the solubilityof potassium chloride solutions at different temperatures variesgreatly.

It is important to note that water softener systems are not alwaysoperated in controlled environments. The temperatures that householdwater softeners are exposed can vary significantly. The changes intemperature fluctuations can have a catastrophic effect on potassiumchloride brine solutions. Since, it is desirable to have highlyconcentrated brine solutions below the saturation levels, the changesfrom higher to lower temperatures can cause re-crystallization of thedissolved potassium chloride. Once initial re-crystallization occurs,crystallization continues and tends to displace the brining solution. Asa result, the remaining brine solution cannot be drawn into the resinbeds for regeneration of the resin beds causing system failure.

The present invention addresses this problem and provides for a processand apparatus for reducing the formation of salt crystals in the brinesolution.

SUMMARY OF THE INVENTION

The present invention when embodied in a water softening system providesa new and improved brine valve in which system failure is prevented as aresult of crystal formation of brine.

The brine valve controls the supply of brine to a conditioning tankduring a regeneration cycle and the supply of water to the brine tank atthe end of the regeneration cycle The brine valve of the presentinvention includes a conduit in communication with the conditioningtank; means for withdrawing brine from a reservoir including apassageway in communication with the brine; and means for supplyingwater to the brine tank wherein the brine tank includes a brine well incommunication with a brine reservoir, the means for supplying waterincluding a first nozzle and a second nozzle in communication with thesupply of water, the first nozzle supplying water to the brine well fordiluting the brine in the reservoir after the regeneration cycle, thesecond nozzle supplying water to a salt material disposed over thereservoir for replenishing brine in the reservoir, the ratio of a flowof water from the second nozzle to the first nozzle is at about 8:1 toabout 4:1. More preferably, the ratio of the flow rates of the secondnozzle to the first nozzle is from about 6:1.

Another embodiment of the present invention is directed to an improvedcheck valve in the brine valve assembly. The check valve provides meansfor withdrawing brine from a reservoir. The check valve includes aflexible membrane, a piston and a spring operatively connected whereinthe supply of water causes the flexible membrane to flex and exert apressure pulse on a volume of liquid in the second conduit whereby thevolume of liquid displaces a float from a seat in the air check

Other embodiments of the invention are contemplated to provideparticular features and structural variants of the basic elements. Thespecific embodiments referred to as well as possible variations and thevarious features and advantages of the invention will become betterunderstood when considered in connection with the detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, partially in cross-section, of a watersoftening apparatus incorporating the present invention;

FIG. 2 is an exploded elevational view of the brine valve assemblyconstructed in accordance with the present invention;

FIG. 3 is cross sectional view of a check valve used in the constructionof the brine valve assembly; and

FIG. 4 is a cross sectional view of an air check used in theconstruction of the brine valve assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and in particular FIG. 1, there is showna water softening system, generally designated by reference numeral 10,that incorporates the present invention. The water softening system isdesigned to soften water when it is delivered to a residence orbusiness. The system as shown, is advantageously designed and operatedto prevent system failure as a result of brine crystallization. Thesystem 10 includes two resin tanks 12, 14 proximally positioned near anupstanding brine tank 16 and a valve assembly 18 that is supported atopthe tanks.

The valve assembly 18 is programmed to selectively maintain one of thetanks on-line with a household water supply system. The off-line tank issubjected to a regeneration cycle and then held off-line until theon-line tank is exhausted. The frequency with which the valve assembly18 switches the tanks 12, 14 from on-line operation to regeneration iscontrolled by metering the usage of softened water or the like. Thevalve assembly 18 is operative to connect one of the tanks to thehousehold water supply and also controls regeneration of an exhaustedtank. The valve assembly maintains a regenerated tank “off-line” untilthe “on-line” tank becomes exhausted. Descriptions of the constructionand operation of a control valves suitable for use in the presentinvention along with a complete description of a dual tank watersoftening system are described in U.S. Pat. No. 3,891,522 to Prior etal., and U.S. Pat. No. 4,298,025 to Prior et al., the disclosures ofwhich are hereby incorporated by reference in its entirety.

The softener tanks 12, 14 are of known configuration and utilize commonwater softening chemicals. Each tank typically includes cylinders 20 ofglass fiber construction. The upper ends of the cylinders 20 arethreaded with female 2½ inch N.P.T. threads for connection to the valveassembly 18. Riser pipes 24, 26 depend centrally through the cylinders20. A pair of screens 28, 30 communicate with the lower ends of theriser pipes 24, 26. Suitable ion exchange softening chemicals, indicatedby reference numeral 40 are positioned in the cylinders 20, 22surrounding the riser pipes 24, 26 and the screens 28, 30. Other resintanks suitable for use in the present invention will be apparent tothose skilled in the art in view of this disclosure. A completedescription of the construction and operation of a resin tank suitablefor use in the present invention can be found in U.S. Pat. No. 4,337,153to Prior, the disclosure of which is hereby incorporated by reference.

The water softening process takes place as hard water passes through thetanks 12, 14. The water is channeled into the tanks 12, 14 and issoftened during its passage downwardly through the ion exchangechemicals 40. Hard water is hereinafter defined as water that containscertain multivalent salts, such as those of calcium or magnesium, whichcan form insoluble deposits in boilers and precipitates with soap. Theresin 40 in the tanks 12, 14 replaces or exchanges the hard ions in thesource water with soft ions. Softened water then enters the risers pipes24, 26 through the screens 28, 30 and is directed back out of the tanks12, 14.

The brine tank 16 is an open ended cylindrical drum formed of suitablemetal or plastic capped by a removable cover 50. The brine tank providesa brine supply system that utilizes common ion replacement salts toregenerate the softening chemicals 40. An upstanding brine well 52 islaterally positioned against a wall 53 in the brine tank 16. Thoseskilled in the art will recognize that the brine well could easily bepositioned in other locations within the brine tank, e.g., centrally.The brine well is an open ended top tubular member formed from suitablemetal or plastic. The lower region of the brine well 52 includesapertures 54 such that the brine solution from a brine reservoir 56extends into the brine well wherein the level of solution in the well 52is at about the same level contained in the reservoir 56.

A screen 58 extends horizontally from wall to wall in the brine tank andaround the brine well 52. The screen is position about one-fourth of theway up the walls of the brine tank 16. The screen includes supportmembers 60 of a fixed length for positioning the screen off the floor ofthe brine tank and for supporting the weight of a granular salt materialdisposed thereon. The granular salt material 62 is deposited in thebrine tank 16 and rests atop the screen 58. The brine solution reservoir56 is then defined below the screen 58. The reservoir communicates withthe valve assembly 18 through a conduit 70, the fluid communicationbeing controlled by a brine valve, generally designated by referencenumeral 80.

The brine valve 80 is positioned in the brine well 52. The brine valveserves a dual function in that it controls both the outflow of brinesolution from the reservoir 56 to the valve assembly 18 during tankregeneration and controls the inflow of water to replenish the brinesolutions used during replenishment. Use of the brine control valve inaccordance with the present invention prevents system failure caused bycrystallization of salt in the brine. For example, crystals formed as aresult of inactivity, temperature fluctuation, salt saturation or in anymanner are prevented from causing system failure.

Referring now to FIG. 2, there is shown an exploded side elevationalview of the brine control valve 80 in the well 52. The brine controlvalve assembly 80 includes the brine conduit 70 that is connected to thevalve assembly 18 via a port 72 in the wall of the tank 16 and providespassage of water during brine replenishment and also permits brine to bewithdrawn during regeneration of the tanks 12, 14. Connected to conduit70 is a tee 82. An opening 84 of tee 82 is connected to an assembly thatis used to draw brine solution from the reservoir 56 to the tank 12 or14 selected for resin regeneration. The tee opening 84 is laterallyconnected by conduit 86 to an elbow 88. The elbow 88 is furtherconnected by conduit 90 to a check valve 100. A rigid tube 102 extendsfrom the check valve 100 and is connected to an air check 104.

Referring now to FIG. 3, there is shown a cross sectional view of thecheck valve 100. The check valve 100 includes a cylindrical body 110with upper and lower openings, 112, 114 respectively. The conduit 90 isconnected to the upper opening 112 by conventional compression fittings116. Located within the body 110 is a piston assembly that includes anumbrella check 116, a piston 118, a quad ring 120 and a spring 122. Theumbrella check 116 is a flexible umbrella shaped silicone seal that ispositioned in the body 110 as shown. As seen best in FIG. 3, the piston118 includes a plurality of bores 118 a. In the preferred embodiment,the piston 118 includes eight bores 118 a each having a diameter of0.027 inches. The umbrella check 116 allows fluid flow form the bores118 a into the conduit 90. However, flow from the conduit 90 into thebores 118 a is substantially inhibited. An umbrella check valve 116suitable for this application is available from Vernay Laboratoriesunder the designation VL 2287-101. In the preferred embodiment, the seal116 is formed from flouro silicone and has a durometer of 57.

The piston assembly functions to allow unidirectional passage of brinesolution in the reservoir 56 through the air check 104 and then throughconduits 102, 90, 86 and 70 during the regeneration cycle. Duringregeneration, the piston assembly decompresses the spring and theumbrella check unseats allowing passage of solution from the reservoir.It has been found that as long as the umbrella check unseats duringregeneration, passage of brine will occur. The lower opening 114 isadapted to receive a compression fitting 124 for seating the pistonassembly and for connecting to rigid tube 102. A screen, not shown, isoptionally positioned within the fitting to prevent any particulate frompassing through the assembly.

The air check assembly 104 includes a base portion 130 and a bodyportion 132. The base portion includes a fluid passageway 134 to thebody portion and is connected to conduit 102. A tubular chamber 136 isdisposed interiorly along a longitudinal axis of the body and is incommunication with the passageway 134. A buoyant ball bearing 138 isdisposed in the chamber 136. A series of horizontal slots 140 extendfrom an exterior surface of the body and are in communication with thechamber 136. The diameter of the passageway at the interface between theboy and base portions is of a smaller diameter than the diameter of theball bearing thereby providing a seat 142 for the ball bearing 138 suchthat when the ball bearing makes contact with the seat the passage ofsolution is prevented. An example of a suitable air check valve for usein the present invention is Model No. FL500, commercially available fromFleck Controls, Inc.

In operation, the ball bearing 138 disposed in the chamber 136 floats inthe brine solution in the reservoir 56. During tank regeneration, thevalve assembly 18 causes a pressure change within the assembly thatcauses brine to be withdrawn from the reservoir. Once the level of thebrine reservoir 56 is at about the height of the lowest horizontal slot140, the ball bearing will become seated within the seat 142 of thechamber thereby preventing further passage of brine from being drawn.Once the ball bearing is seated, a slight vacuum on the ball bearing 136prevents the ball bearing from being dislodged and as such, preventsfurther withdrawal of brine from the reservoir. After the selected tank,12 or 14, is regenerated with brine, the valve assembly signals thesystem 10 to replenish the brine expended during regeneration.

During brine replenishment, the valve assembly 18 directs pressurizedwater into conduit 72 which causes a brief pulse of pressure to beexerted on the umbrella check 116 of the check valve 100. The umbrellacheck seats and causes the piston assembly to move downward compressingthe spring and exerting a counter-pressure of a small volume of solutionin conduit 102. Consequently, the solution in conduit 102 pulses throughthe air check assembly 104, thereby releasing the vacuum on the ballbearing 136 in seat 142. Once the vacuum is removed, the ball bearing136 is free to float in the chamber. As such, the ball bearing 136 willrise to the height of the brine solution in the reservoir 56 as it isbeing replenished or to the ceiling in the air check chamber dependingon the height of the reservoir. The actual brine replenishment will bediscussed in greater detail below. The Applicants have found thatwithout the back pulse provided by the check valve, the water treatmentsystem would lock up during subsequent regeneration cycles. For example,simple ball check valves have been found to be inadequate and prone tohydraulic failure during multiple regeneration cycles.

The brine replenishment system is connected to the other opening 140 oftee 82. The brine replenishing assembly includes a rod and floatassembly. The rod and float assembly, which will be described in detailbelow, is connected to the tee opening by means of an adapter 143 havinga threaded end portion and a stem portion The stem portion isconventionally connected to the tee 82. Preferably, a metal screen (notshown) is inserted in the tee prior to attaching the stem to the tee. Apress-in check valve (not shown) is inserted into the threaded end ofthe adapter 143. The threaded end of the adapter 143 is then connectedto the rod and float assembly. A suitable press-in check valve isavailable from Flomatic Systems, Inc. and has a designation of RC-256.

The rod and float assembly 160 includes a refill valve 162. The refillvalve includes a cylindrical body 164 with a lower opening 166 and anupper opening 168. A rod 170 extends through openings in the sidewall ofthe body and controls the opening and closing of a valve body (notshown) disposed in the refill valve. The rod 170 is pivotally attachedto a rigid tube 174 wherein the distal end of the tube includes abuoyant float 176. As the height of the reservoir 56 changes duringregeneration cycles, the float 176 causes the rod 170 to move the valvebody 172 upwardly or downwardly in the body thereby opening or closingthe refill valve depending on the height of brine solution in thereservoir 56. For example, if the brine reservoir is low, the float andthe corresponding angle of the rod will cause the valve body to rise andprovide passage of water thereby permitting replenishment of the brine.In contrast, as the brine reservoir is replenished, the valve bodylowers and slowly closes the passageway, whereby passage of water isprevented. The predetermined height of the rigid tube 124 and the float176 are factors that control the amount of brine to be replenished.

The lower opening 166 of the refill valve is connected to a dual nozzleassembly by means of conduit 180. The dual nozzle assembly includes afirst spray nozzle 190 that is positioned to release water in the brinewell and a second spray nozzle 200 that is positioned to release waterdirectly onto the granular salt bed. The conduit 180 is connected to tee182. A threaded reducer bushing 183 is connected to the one opening ofthe tee 184. The first spray nozzle 190 is connected to the bushing 183and as such, is positioned to spray water during brine replenishmentcycles within the brine well 52. An elbow 188 is connected to an otheropening 186 of tee 182. A flexible conduit 192 is connected to the elbow188 and extends to a port 194 in the brine well 52. The port 194 islocated above height of the granular salt material 62. The conduit 192is connected to a connector 196 and elbow 198 that are secured to theport 194 in the brine well wall. A threaded reducer bushing 202 isattached to the elbow. The second spray nozzle 200 is threaded into thebushing 202 and is positioned to release spray directly onto thegranular salt 62. Spray nozzles suitable for this application areavailable from Hago Manufacturing Company, Incorporated.

During the time when brine is being drawn from the reservoir, thepress-in check valve (not shown) located within the fitting 143 inhibitsthe flow of air into the brine conduit 70 via the nozzles 190, 200.

The flow rates of each individual nozzle 190, 200 are preferablycontrolled wherein a flow ratio at the second nozzle 200 compared to thefirst nozzle 190 is from about 4:1 to about 8:1. More preferably, theflow ratios are at about 6:1. The first nozzle 190 sprays pressurizedwater directly into the brine well 52 and as such, dilutes the residualbrine in the reservoir with water and/or dissolves any salt crystalsformed. Simultaneously, the second nozzle 200 sprays water over thegranular salt 62 to replenish the brine reservoir 56 to a leveldetermined by positioning of the rod and float assembly 160. Since thewater from the spray material must first pass through the granular saltmaterial 62, it is believed that the water from the first nozzlepreferentially dilutes the brine reservoir to ensure that the solutionis definitely lower in saturation. The Applicants have found thepreferred ratio of flow rates of each nozzle are important to maintain atarget concentration of brine in the reservoir and be effective inpreventing recrystallization. The aforementioned range of flow rateshave been found to be effective for preventing system failure as aresult of salt formation in the reservoir.

The granular salt material 62 preferably includes soft ion donorsincluding, but not limited to, salts such as potassium chloride andsodium chloride. Other salts suitable for use in water softening systemswill be apparent to those skilled in the art in view of this disclosure.The use of the dual nozzle assembly with the aforementioned flow ratesdilutes and/or dissolves the brine reservoir during the brinereplenishment cycle prior to or simultaneous with brine replenishment.The present invention is especially advantageous with those softeningsalts that exhibit solubility differences over a range of temperatures,e.g., potassium chloride.

Many modifications and variations of the invention will be apparent tothose skilled in the art in light of the foregoing disclosure.Therefore, it is to be understood that, within the scope of the appendedclaims, the invention can be practiced otherwise than has beenspecifically shown and described.

1. A brine valve mechanism which controls the supply of brine to aconditioning tank during a regeneration cycle and the supply of water tothe brine tank at the end of the regeneration cycle, the brine valvemechanism comprising: a) a conduit in communication with theconditioning tank; b) means for withdrawing brine from a reservoircomprising a passageway in communication with the brine; and c) meansfor supplying water to the brine tank wherein the brine tank includes abrine well in communication with a brine reservoir, the means forsupplying water comprising a first nozzle and a second nozzle incommunication with the supply of water, the first nozzle supplying waterto the brine well for diluting the brine in the reservoir after theregeneration cycle, the second nozzle supplying water to a salt materialdisposed over the reservoir for replenishing brine in the reservoir, theratio of a flow of water from the second nozzle to the first nozzle isat about 6:1.
 2. A brine valve mechanism which controls the supply ofbrine to a conditioning tank during a regeneration cycle and the supplyof water to the brine tank at the end of the regeneration cycle, thebrine valve mechanism comprising: a) a first conduit in communicationwith the conditioning tank; b) means for withdrawing brine from areservoir wherein the means for withdrawing brine comprises a one wayvalve, an air check immersed in a volume of brine, and a second conduitconnected to the valve and the air check such that there is a fluidpassageway with the conditioning tank, the valve comprising a flexiblemembrane, a piston and a spring operatively connected wherein the supplyof water causes the flexible membrane to flex and exert a pressure pulseon a volume of liquid in the second conduit whereby the volume of liquiddisplaces a float from a seat in the air check; and c) means forsupplying water to the brine tank wherein the brine tank includes abrine well in communication with a brine reservoir, the means forsupplying water comprising a first nozzle and a second nozzle incommunication with the supply of water, the first nozzle supplying waterto the brine well for diluting the brine in the reservoir after theregeneration cycle, the second nozzle supplying water to a salt materialdisposed over the reservoir for replenishing brine in the reservoir, theratio of a flow of water from the second nozzle to the first nozzle isat about 6:1.
 3. A method of operating a water treatment system thatincludes a pair of ion-exchange water softener tanks connectable to asource of pressurized water and with a water system to supply softenedwater to the Water system, the tanks each being capable of regenerationby flushing with a regeneration solution to replenish depleted ions, themethod of operating the water treatment system, comprising: a)regenerating a selected one of the tanks with a brine solution whereinhard ions are removed from a resin in the tank and exchanged with softions, the brine solution being contained in a container in communicationwith the selected tank wherein the container includes a salt materialdisposed on a screen above a brine reservoir and further includes abrine well in communication with the brine reservoir, the brinereservoir defining the brine solution; b) replenishing brine after thebrine regeneration cycle is complete wherein the step of replenishingthe brine includes; (i) flowing water from a first nozzle directly intoa brine well of the system for initially diluting the brine in thereservoir, and (ii) flowing water from a second nozzle directly onto asalt material for generating additional brine solution in the reservoir.4. The method according to claim 3, wherein the water flow rate throughthe second nozzle is in the range of about four times to about eighttimes the water flow rate through the first nozzle.
 5. The methodaccording to claim 3, wherein the flow rate of water through the secondnozzle is about six times greater than the flow rate of water flowingthrough the first nozzle.
 6. A mechanism for producing a fluid pulse ina conduit used to draw solution from a reservoir, comprising: a)structure defining a chamber slidably supporting a piston; b) a biasingelement for urging said piston towards a first position; c) said pistonincluding at least one piston passage for allowing fluid flow from afirst fluid passage to a second fluid passage; d) check valve carried bysaid piston for controlling fluid flow through said piston passage, suchthat fluid flow from said first fluid passage to said second fluidpassage is permitted by said check valve; and, e) said check valveinhibiting fluid flow from said second fluid passage through said pistonpassage, such that fluid flow out of said second fluid passage exerts aforce on said piston causing said piston to move away from its firstposition and producing a fluid pressure pulse in said first fluidpassage.
 7. The mechanism of claim,6, wherein said first fluid passagecommunicates with a check valve which is opened in response to saidfluid pressure pulse.
 8. The mechanism of claim 7, wherein saidmechanism forms part of a brine system and operates to unseat a ballcheck valve that controls the communication of brine solution from areservoir into a brine supply conduit.